tree be5bbfdd1f8c78763ddf6c04fd5a3a29bad76e58
parent 2bb52b47e7f420bbed4192efca20a9de8ff4fa08
author James Hogan <james.hogan@imgtec.com> 1490955798 +0100
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1491993673 +0200

metag/usercopy: Fix alignment error checking

commit 2257211942bbbf6c798ab70b487d7e62f7835a1a upstream.

Fix the error checking of the alignment adjustment code in
raw_copy_from_user(), which mistakenly considers it safe to skip the
error check when aligning the source buffer on a 2 or 4 byte boundary.

If the destination buffer was unaligned it may have started to copy
using byte or word accesses, which could well be at the start of a new
(valid) source page. This would result in it appearing to have copied 1
or 2 bytes at the end of the first (invalid) page rather than none at
all.

Fixes: 373cd784d0fc ("metag: Memory handling")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: linux-metag@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>